The present invention is related to integrated circuits. More specifically, the present invention can be applied to devices used controlling power supply. According to various embodiments, the present invention provides various novel techniques for power factor correction in a power system. Merely by way of example, the present invention can be implemented in conjunction with transition mode power factor controller. It is to be appreciated that the present invention has a broad range of applications.
Since the Benjamin Franklin's discovery of electricity, a wide ranges of devices have been developed. Various electrical devices—such as light bulbs, telephones, record players, to just name a few—have change lives of human beings forever. As people rely more and more on electrical devices, the need for electricity increases dramatically. To satisfy the demand for electricity, large power generators have been built. Typically, power generators are far away from the customers who need electricity, and thus electricity need to be transferred for a large distance. With invention of inductor motor by Nikola Tesla, alternating current (AC) becomes adopted for long-distance power transmission.
One of characteristics of AC power lines has been power factor. Power factor is a function of power being delivered and power being actually consumed. For efficient transferring and usage of power, power factor correction (PFC) devices are often needed. Many regulatory bodies have imposed regulations regarding PFC. For example, the International Electrotechnical Commission (IEC) has imposed standard IEC 100-3-2, which requires electrical devices to use input stages with topologies other from a simple off-line front end which contains a bridge rectifier and capacitor. In addition, there are also various system requirements that require the use of PFC devices.
Over the past, various types of PFC devices have been developed and used. For example, various conventional PFC techniques, such as multiplier-based transition mode power factor corrector, have been developed. Unfortunately, these conventional techniques are often inadequate.
Therefore, it is desirable to have improved system and method for power factor correction controller.